Originally Posted by RealHJ

I don't think it's blocked. Just booked. From my experience, many JAL flights will get booked within a few minutes (sometimes seconds) of being released at 330 days out. If you want a specific flight on a specific date, you have to book at 330 days out 10am JST and be quick about it. That is especially so during popular travel times. (So now is the time to book for December...the time to book for September has long ago passed.)

There can be more availability opened up as existing bookings get canceled (not sure does it always go back into inventory, but most of the time it probably does). Best way to get that is to waitlist. Also closer in more tends to be released, like a month, two weeks, one week in, depending on how full (or not) the flight is, more tends to be released closer in.

It's advantageous to use JAL JMB to book further out and waitlist. For very close in bookings you actually cannot book it with JAL, as they restrict it. Close in bookings for the next day or thereabouts you can only book with other programs. (I know, not logical...but that's the way it is.)